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I am totally new to electronics and don't know much but am trying to create a project that uses a 29rpm 6v DC motor. I was wondering if I were to use a higher voltage battery ( a 9v battery) would it be able to power the lower voltage motor?

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    \$\begingroup\$ I am voting to close the question as a duplicate of Would a 9V alkaline power a 12V DC motor? \$\endgroup\$ – Charles Cowie Jul 16 '19 at 20:12
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    \$\begingroup\$ That is impossible to say. It depends on the motor and what it's driving, on the battery and thermal circumstances. Generally, if something is rated for voltage A, and you operate it at voltage B higher than A, it's likely to fail. Why else would someone rate it for A? \$\endgroup\$ – Marcus Müller Jul 16 '19 at 20:13
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The speed of a brushed DC motor is roughly proportional to the voltage applied, given the same countertorque.

You are running the motor at 1.5 times the rated voltage, thus you get 1.5 times the speed.

There's a reason that motor is designed for 6V only. DC brushed motors are very forgiving, even the commutator and the bearing should stand 1.5 times the design speed for a long time.

  • But the gears don't.

It's most likely a plastic gearbox. Running it at overspeed will destroy the innermost gear very quickly. Don't do it.

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  • \$\begingroup\$ Thank you for your response. And instead of using a single 9v battery, what else could I use instead? \$\endgroup\$ – Evan Laviolette Jul 16 '19 at 20:19
  • \$\begingroup\$ There are 6V batteries in the market, for example as lead accumulators. google.com/search?q=6V+battery&tbm=isch, but also as alkaline cells. If you need something smaller, use a battery box with four AA or AAA cells. \$\endgroup\$ – Janka Jul 16 '19 at 20:21
  • \$\begingroup\$ You could use a buck regulator to convert the 9 volts to a constant 6 volt source. The added bonus is that your gearbox would spin at a reliable/consistent speed while still extracting most of the energy from your battery \$\endgroup\$ – Kent Altobelli Jul 16 '19 at 20:34
  • \$\begingroup\$ "DC brushed motors are very forgiving, even the commutator and the bearing should stand 1.5 times the design speed for a long time." - that may not be true. Before brushless motors were commonplace we sometimes ran 6V rated brushed motors at 9.6V in radio controlled models - and lifespan was greatly reduced. Cheap brushed motors used in 'toy' gearboxes often have metal brushes and plastic bearings, which barely survive even at the rated voltage. \$\endgroup\$ – Bruce Abbott Jul 16 '19 at 21:12

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